Lustar &ndash; Hydro-Sponge III Filter for Aquariums up to 40 Gallons Easy to clean, just rinse and squeeze in used aquarium water. Never use tap water One inch diameter lift tube allows for high volume water flow and allows use of power head without adapters Made from Proprietary Patented Sponge Foam for the highest mechanical debris capacity and bio capacity The Hydro-Sponge traps waste particles, mechanically cleaning the water without trapping baby fish Can be used in the vertical or horizontal position. Heavier base with a raised bottom